In toasters of this type, the measuring device as well as the detector must remain reliable over a long period of time no matter what the conditions of use. In the case in which the body to be toasted, for example a slice of bread, is correctly placed between the heating means and the detector, the measuring device ensures a normal toasting cycle and permits obtaining a degree of toasting selected by the user. By contrast, in the case of poor positioning of the body to be toasted, and even in the case of forgetting to insert this body into the toasting chamber, the detector receives directly the radiation emitted by one of said heating means and is hence blinded. This intense radiation is not only harmful to the electronic components of the detector, but also is seriously damaging to the measuring device if no operation of ceasing the radiation is taken promptly.
To overcome these defects, it has been provided either to place movable shutters in front of the detector, or to increase the sensitivity of the measuring device so as to obtain instantaneous stopping of the supply control device in case of blinding the detector. The first solution is too costly and difficult to use. As to the second solution, it causes the user to make a mistake, because he believes, when the body to be toasted is improperly positioned, that the toaster will not operate because of the stopping of the supply and the starting of the operation of the toaster are consecutive during continuous toasting cycles.